A low profile aperture coupled antenna with broadband circular polarization characteristics for UHF RFID applications

2018 ◽  
Vol 29 (6) ◽  
pp. e21688
Author(s):  
Zijian Xing ◽  
Bo‐Yu Chen ◽  
Chow‐Yen‐Desmond Sim
Keyword(s):  
Circular Polarization ◽  
Uhf Rfid ◽  
Low Profile ◽  
Polarization Characteristics ◽  
Rfid Applications

scholarly journals Single-Fed Broadband CP Bidirectional Antenna with Double-Layer Diagonally Aligned Plates for Universal UHF-RFID Applications

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Sitthichai Dentri ◽  
Khanet Pookkapund ◽  
Bancha Luadang ◽  
Prayoot Akkaraekthalin ◽  
Chuwong Phongcharoenpanich
Keyword(s):  
Circular Polarization ◽  
Lower Layer ◽  
Axial Ratio ◽  
Double Layers ◽  
Impedance Bandwidth ◽  
Rectangular Plates ◽  
Uhf Rfid ◽  
Alignment Technique ◽  
Half Power ◽  
Rfid Applications

This research proposes a single-fed broadband circularly polarized (CP) bidirectional antenna operable in 840–960 MHz frequency band for readers of universal UHF-RFID applications. The proposed antenna is comprised of upper-layer conductor, lower-layer conductor, and wall patches. The upper-layer conductor consists of two diagonally aligned rectangular copper plates with a feeding gap at the center, and the lower-layer conductor is of two diagonally adjoined rectangular plates. The upper- and lower-layer conductors are adjoined with the wall patches. The diagonal alignment technique of the upper- and lower-layer plates was used to realize circular polarization and improve 3-dB axial ratio (AR) bandwidth. The double layers were deployed to improve impedance bandwidth (|S11| < −10 dB) and achieve bidirectional radiation pattern. The simulated impedance bandwidth and 3-dB AR bandwidth were 772.19–1014.6 MHz (27.13%) and 675–1000 MHz (38.80%), and the corresponding measured results were 759–1011 MHz (28.47%) and 648–1110 MHz (52.55%). The simulated LHCP/RHCP half-power beamwidth (HPBW), 3-dB AR beamwidth, and gain were 56° – 90°/54° – 92°, 60° – 104°, and 4.94 – 5.89 dBic, while the corresponding measured results were 52° – 98°/62° – 97°, 96° – 126°, and 4.28 – 5.72 dBic. As a result, the single-fed broadband CP bidirectional antenna is applicable to universal UHF-RFID readers. Besides, the novelty of this research lies in the use of diagonal alignment of conducting plates to achieve circular polarization and wider AR bandwidth.

scholarly journals Circularly Polarized Low-Profile Antenna for Radiating Parallel to Ground Plane for RFID Reader Applications

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Kittima Lertsakwimarn ◽  
Chuwong Phongcharoenpanich ◽  
Takeshi Fukusako
Keyword(s):  
Circular Polarization ◽  
Ground Plane ◽  
Axial Ratio ◽  
Main Beam ◽  
Uhf Rfid ◽  
Printed Antenna ◽  
Circularly Polarized ◽  
Maximum Gain ◽  
Low Profile ◽  
Parallel Direction

This paper presents a low-profile printed antenna with double U-shaped arms radiating circular polarization for the UHF RFID readers. The proposed antenna consists of double U-shaped strip structures and a capacitive feeding line to generate circular polarization. A part of the U-shaped arms is bent by 90° to direct the main beam parallel to the ground plane. From the results,-10 dB|S11|and 3 dB axial ratio of the antenna cover a typical UHF RFID band from 920 MHz to 925 MHz. The bidirectional beam is obtained with the maximum gain of 1.8 dBic in the parallel direction to the ground plane at the 925 MHz. The overall size of the proposed antenna including ground plane is 107 mm × 57 mm × 12.8 mm (0.33λ0× 0.17λ0× 0.04λ0).

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